Boiler



March 1 Filed AL S BOILER P. o. KOCK 3 Sheets-Sheet 2 HIS'MTURAZEYS:

March 1s, 1.958 r 2,827,023

BOILER Filed Aug. 9, 1956 3 Sheets-Sheet 3 Wan. Paula Keck .EUS'ATYUMSZUnite BOILER Paul 0. Kock, Columbus, Ohio, assignor to BituminousCoalResearch, Inc., Pittsburgh, Pa., a corporation of DelawareApplication-August 9, 1956, SerialNo. 69313088 Claims. (Cl. 122-265)rates atent C or both, has been relatively high totry to increase thelength of thepath of travel of the gases, particularly beforeencountering any substantial cooling surface. Otherwise, suchsurfacemight become fouledby the condensation thereon of volatiles in gasesfrom coals or briquetted solid fuels. In some cases such volatiles-mighteven pass through a boiler with attendant hazard due to a possibilityofexplosion and/or with thecreation of smoke. In some situations thespace economy of'such water-tube boilers might be so poor as to causethem to be rejected in favor of-lower headroom boilers such asexistin-the fire-tube boiler field. in'other cases, prior water-tubeboilers have-utilized water tubes'of different lengths in a singleboiler and/ or have 'required'a' special construction not-readilylending-itself'to a design for flexibility incapacity or duplication forrepeated installations.

In my invention disclosed herein, deficiencies of prior boiler practiceshave been overcome. Thus, in watertube boiler embodiments of myinvetnion, there is a material economy in the space requirement'such asheadroom.- Moreover, the path traveled by gases is relatively markedlylengthened with heightened assurance of complete combustion andinhibition of any explosion hazard or smoke nuisance even when burning asolid fuel like bituminous coal or the like. Thus, clusters of watertubes maythereby be positioned far enough back in the gas' flowpath toprevent material condensation and/ or fouling of tube surfaces by suchcondensible volatiles, for example, as might originally have beenpresent. Tubes utilized in embodiments of this invention preferably aremade the same length with relative improvement in water circulationpattern and relatively higher heating efiiciency because of the newconstruction. Still further, boiler embodimentsof my invention areflexible in terms of boiler capacity design alterable to a greatercapacity, e. g., by the addition of one or more vertical banks of watertubes without changing the over-all length or character of such aboilerembodiment.

titer-objects and advantages will be apparent from the followingdescription and from the accompanying drawings, which are illustrativeof one embodiment only, in which Figure 1 is a view in side elevation ofone embodi merit of a water-tube boiler. constructed in accordance withthis invention;

'ice Figure 2 is a front view of the boiler shown in Figure 1;

Figure 3 is a rear view of the boiler shown in Figure 1;

Figure 4 is a plan View of the boiler shown in Figure 1 taken alonglino-IV-IV of Figure 7;

Figure 'S is'a' view in section taken along line VV ofFigure 4;

Figure 6 is a view in section taken along line VlVI of Fi'gu're '7 and"Figure 7 is" a view taken along line VII-Vii of Figure 5% Referring totliedtawiirgs, a water-tube boiler 10 constitutes one embodiment of myinvention. It is shown with a commercial formof automatic stoker 11having ashaker grate 1-2- to-supply'solid' fuel like coal orcarbonaceous briquettes-to boiler 10 for burning; therein, althoughother fuels like fuel gas and oil may successfully be burned'inanew-boiler of this invention; Boiler 10 is positioned on a relativelylow foundation or base'13, the=main structuralmembers of which, ifdesired, may be downward extensions of the shell of boiler 10: Ashes mayb'eremoved from boiler ltl'by an ash removal conveyor- 14- when solidfuel'is burned therein and combustion air at suitable pressure may besupplied as undergrate primary combustion air by a forced draft blowerl5 or'by an induced draftfan (not shown) in the flue connection lo,orbyboth, as desired. Flue 16 communicates with a gas dome 17 in boiler10 through a breeching connection 18-, the other end of flue l6 enteringa stack-for waste gaseous products of combustion. Steam may be generatedby boiler ltiand collected in a'steam space 19 above the watersurface-29. Such steam may be discharged throughamain steam .outlet 21connected to a main steam pipe-22.

A 'couplingZS communicates with the interior of water leg 45 near thebottom 24 so that-feed-water-fr'om a pipe 25 may be supplied to boilerit) when valve26is opened. Coupling 23 may, alternatively, be connectedto'a drain pipe 27 when a plug valve 28 -is opened to drain or blow outsome or allot the water in boiler 16'.- Cleanoutdoors 29'may beprovidedon one-or both sides of embodiment lll'of my newboiler and afurnace access door 3ilmay be provided with-other suitable access andinspection openingprovisions-including front access doors 31 and 32respectively on boiler it) and below stoker 11', as-will'be readilyunderstood by those having'skill in the boiler art to whom-thisinventionisdisclosed.

Boiler 10' is provided with a hollow shell made up of an outer shell33"and'an inner shell 34. Outershell 33 may have a top 35 in the form ofa wagon top or other form, side plates 36, afront plate -37 and a rearplate 38. Front andrear plates 37 and 33 may-be respectively providedwith plug sheets 3? and 46 respectively'pierced in registry with-thewater-tubes in-boiler 1i), suchpiercings being tapped 'and plugged bythreaded plugs 41 which can be removed when the insides of particularwater tubes are to be cleanedor particular water'tubes-are-tobe replacedthrough the openings-in'theplug sheets 39- and 49, an expander-toolgenerally being used toexpand the ends of 'thewater"tubesintotight'binding relation to the front and-reartu'oe sheets 42andi3respectively comprising thefront and rear-platesof inner'sh'ellCMi-IThe plates 4-2 and 43' are respectively joi'nedat the'bot-torn-to plates37 ancl SSwhile side plates 44 of inner shell 34 are-respectivelyjoined. at the bottom to side plates 36 of outer shell 33 to providefront and-rear water legs 45 and 46 respectively and'side water legs4'7, in'boiler 16'. The inner and outer shells 33 and 34 may otherwisebesuitably stayed in spaced relation to provide the water and steamspace'required or the'water space" required where a boiieroi thisinvention is to be used as a hot Water.- supplier: without the:generationof i steam:

in a new boiler of this invention. I tinued upwardly by a platepartition or baffie 51 extend- In the illustrated embodiment, a verticalwater wall partitionAS is'provided extending between front water leg 45and rear water leg 46 extending in height from the top of base 13approximately midway to the level 49 of the top row of water tubes inboiler 10. The top' 56 of partition 48 is preferably pitchedor'tilted'upwardly from rear to front-at the slope given to the watertubes in boiler 10.1 Water partition 48 is provided with'pipe 7;

ing to level 49 in height and extending in length from tube sheet 42 tothe forward edge 52 of a partition opening 53 in the longitudinal planeof baffie 51;

A fire zone 54 is provided in boiler 10 between the left side water leg47, grate 12, partition 48 and a roof in the form of a bafile 55 of castrefractory or laid block which may be supported in part by a horizontalrow 56 of water tubes and the top of partition '48, such roof baiileextending from rear water leg 46, that'is, from rear'tube sheet43 to itstransverse forward edge 57 defining an opening 58 for gaseous combustionmaterials i and products leading from longitudinally extending fire zone54 into a longtudinally extending radiant zone 59 superposed thereabovein the boiler 10 embodiment.

I Radiant zone59,"as shown, is bounded by roof baffle 55 and tube row 56along the bottom, by water leg 47 t on the left, by a horizontal row 60of water tubes extending laterally to plate bafile 51 and by a ceilingslab 61 on the top, and, by a vertical row 62 of water tubes on theright adjoining bafile 51. Ceiling slab 61 may be made of castrefractory or laid refractory blocks supported on the water tubes atlevel 49 as shown; The ceiling slab extends wholly across the radiantzone-59 and from one end thereof to the other and also across the 7 7top of water tube cluster zones 63 and 64, save for an opening 65therein for the passage of waste gaseous combustion products into gasdome 17. Thus, it will be noted that flame and gaseous products ofcombustion are provided with a relativelylongtravel in fire zone 54 andt v v p being turned by an electnc motor 75 mounted on a radiant zone59-by which time combustion of all volatiles .of water-cooled tubesurfaces in the flow path of such gaseous products with, the result thatcondensation on such water-cooled surfaces and fouling thereof isinhibited or wholly avoided evenwhen relatively high-volatilescontainingsolid or other fuels are utilized.

The gaseous products of combustion then'pass through partitionopening'53 into' tube cluster zone 63. The verti'cal banks 66:0f watertubes in cluster zones 63, and 64 may extend downwardly from level 49 toa'position'close V to the bottom of boilerlO. All of such tubes, as areall of the tubes in'boiler 10, inclusive of the tubes iu rows .56, andin bank 62, are of'equal length- Therm pecthe ends of the tubes extendthrough and are sealed 7 7 in the respective tube sheets 42 and 43around the out- 2 (sides of the ends of such water tubes so thattarelatively high velocity water circulation'pattern is achieved withwater flowing downwardly in the rear water leg .46, entering therrearlower ends of all of the water tubes and exiting at thefront ends ofsuch water tubes in front water leg145 before ascending to pass overand. across" thefltop of inner shell'34'beneath the steam space 19., The'water surface 20 is preferably maintainediat the 'should becomplete'before there is material interposition possible at the verticalcorners between the inner and outer shells 33 and 34 which has value inafiording a I place for the deposit of any sediment which can bewashedout periodically when Wash-out plugs 67 are removed for suchpurpose. 7

A refractory floor slab 68, which'may be cast refractory or laidrefractory brick, is provided to close the bottom of cluster zones 63and 64; Slab 68 may be supported on a plate 69 supported on base 13 orfastened to the underside of boiler 10. Zones 63 and 64 may be partiallyseparated by a transverse curtain baflle 70 extending across the fullwidth of those zones and downwardly from ceiling slab 61 to lower edge 1above slab' 68 so as to provide an opening under edge 71 from zone 63into zone 64 for the gaseous products of combustion which give upfurther heat to the tubes in banks 66 in zone 64 before exiting asthrough ceiling opening 65 into gas dome 17 and from thence throughbreech connection 18 into flue 16 and the 'stack which normally would beconnected to line 16. The heating gases by having "to pass beneath edge71 have their paths of travel in the cluster zones 63 and 64 lengthenedfor additional increase in heating efficiency provided by a boiler suchas boiler 10 with its materially increased'path of heating gas .travelstarting in fire zone 54 as the first pass, then going through the firezone opening forwardly of edge 55 to enter the second pass extending thelength of radiation zone 59 where additional heat is given up to thescreening tubes 60 and 62 before the heatinggases pass 'through' thepartition opening 53 and move in their third pass 7 over the clusteredwater tubes in cluster zone 63, the

fourth pass coming as the heating gases pass the curtains bafile-76 andmove through the clustered watertubes in cluster zone 64 with the fifthpass for such gases.

through gas dome 17, providingadditional heat release to the waterthrough a crown sheet 72 at the top of inner shell 34; The respectivegas openings between zones'are' preferably sized to take care of changeinvolurne of gase-' ous flow therethr ough occasioned by combustion andheat transfer which occurs in the course of flow travel in new 7 boilersmade in accordance with this invention.

Although variousfuels may be utilized in a boiler; V

made in accordance with this invention, boiler 10 is illustrated asbeing automatically supplied with solid fuel like coal by a stoker 11having a coal hopper 73 above the :forward end of its grate 12, arotating feed roller 74 tstoker base 76 which may be on an extension ofbase "13. Grate 12 may be in the form of a shaker grate slidof the ashremoval conveyor 14, so that they can be discharged through a spout8 2.An electric motor 83 may be provided and connected With the shaft ofscrew to turn it when boiler 11} is operating on coal.

Water legs of boilerlG;

Grate 12 extends'through a 'front opening 84in the boiler shellat thebottom of front Water leg 45 and may be shaken back .and forthinccnventional mannerbya grateislide end 85 connected by-a'shaker link86' to a rocking arm 87 rocked by an eccentric conuectiontheree Vof'toan electric motor 88. Combustion air for the'burn ing offuel ongrate 12 in fire zone 54 enters ba'sef13 through opening 89bcneath slab68 and enters the underside of grate l2 past the front end 90 0f asidewall 91, extending forwardlyalong the side'of ash pit 78. Suchcombustionair may be at ambient temperatureyor preheated, and'ma'y'receive heat in passing beneath the floor a of the cluster zones63 and 64. Further, if desired, over;

fire combustion air may, if desired, be supplied into fire.

zone 54* by nozzles or. otherwisethro'ugh one or more enemas Variousmodifications may be made in the illustrated embodiment of my inventionand in other embodiments thereof without departing from the spirit of myinvention or the scope of the appended claims.

I claim:

1. In a water tube boiler, in combination, a hollow shell having waterlegs at the sides and ends, the inside of said shell defining aninterior space for said boiler, a longitudinally extending fire zone insaid space, a lower vertical water-cooled partition defining the innerside of said fire zone, said partition being intermediate the sides orsaid space, a horizontal refractory roof bafile defining the top of saidfire zone, said roof bafiie being intermediate the top and bottom ofsaid space, a radiant zone extending the length of said space insuperposed relation to said fire zone, an upper vertical partitiondefining the inner side of said radiant zone, said upper partition beingintermediate the sides of said space, a horizontal refractory ceilingdefining the top of said radiant zone, said ceiling being in the upperportion of said space adjacent between the sides of said boiler butbelow the inside of the top of said shell to form a gas dome, said firezone and radiant zone having a passage therebetween at one end of saidspace to provide a vertical re-entrant turn for gases passing from saidfire zone to said radiant zone, water tubes extending the length of saidboiler in cluster zones in longitudinal registry in said space on theother side of said partitions from said fire and radiant zonesrespectively, said upper partition having a passage from said radiantzone at the other end of said space into the adjacent one of saidcluster zones to provide a horizontal re-entrant turn for gases passingfrom said radiant zone into said cluster zone, a transverse curtain bafile extending downwardly from said ceiling and positioned intermediatethe ends of said tubes in said cluster zones, said curtain baffie havingits lower edge spaced above the bot tom of said cluster zones and belowsaid passage through said upper partition to provide a vertical turn forgases passing from one cluster zone to another, and an opening in saidceiling for gases from said cluster zones to pass into said gas dome onthe other side of said curtain bafi'le from said passage from saidradiant zone, and a flue connected to said gas dome for gases leavingsaid boiler, said flue being spaced from said opening through saidceiling into said gas dome.

2. In a Water tube boiler, in combination, a hollow shell having waterlegs at the sides and ends, the inside of said shell defining aninterior space for said boiler, a longitudinally extending fire zone insaid space, a lower vertical partition defining the inner side of saidfire zone, said partition being intermediate the sides of said space, ahorizontal roof bathe defining the top of said fire zone, said roofbafiie being intermediate the top and bottom of said space, a radiantzone extending the length of said space in superposedrelation to saidfire zone, an upper vertical partition defining the inner side of saidradiant zone, said upper partition being intermediate the sides of saidspace, a horizontal ceiling defining the top of said radiant zone, saidceiling being in the upper portion of said space adjacent but below theinside of the top of said shell to form a gas dome therebetween toprovide a vertical re-entrant turn for gases passing from said fire zoneto said radiant zone, Water tubes extending the length of said boiler, acluster zone in said space on the other side of said partitions fromsaid fire and radiant zones respectively, said upper partition having apassage from said radiant zone into said cluster zone to provide ahorizontal re-entrant turn for gases passing from said radiant zone intosaid cluster zone, and an opening in said ceiling for gases from saidcluster zone to pass into said gas dome after passing through saidcluster zone, and a fine con nected to said gas dome for gases leavingsaid boiler, said flue being spaced from said opening into said gasdome.

3. In a Water tube boiler, in combination, a hollow shell having Waterlegs at the sides and ends, the inside of said shell defining aninterior space for said boiler, a longitudinally extending fire zone insaid space, a vertical partition defining the inner'side of said firezone, said partition being intermediate the sides of said space, ahorizontal roof bafile definingthe top of said fire zone, said roofbaffle being intermediate the top and bottom of said space, a radiantzone extending the length of said space in adjoining relation to saidfire zone, said fire zone having an opening for passing gases into saidradiant zone, a vertical partition defining the inner side of saidradiant zone, a water tube cluster zone adjoining said radiant zone,water tubes'in said cluster zone, a ceiling defining the top of saidcluster zone, said ceiling being in the upper portion of said spaceadjacent but below the inside of the top of said shell to form a gaschamber therebetween, said radiant zone having an opening for passinggases into said cluster zone, said two first-mentioned openings beingspaced from each other, said cluster zone'having an opening for passinggases into said gas chamber after said gases have passed from saidradiant zone and through said water tubes in said cluster zone, and aflue connected to said gas chamber for gases leaving said boiler.

4. In a water tube boiler, in combination, a hollow shell having waterlegs at the sides and ends, the inside of said shell defining aninterior space for said boiler, a longitudinally extending fire zone insaid space, a partition defining the inner side of said fire zone, saidpartition being intermediate the sides of said space, a horizontal roofbaffle defining the top of said fire zone, said roof baflle beingintermediate the top and bottom of said space, a radiant zone extendingthe length of said space in adjoining relation to said fire zone, saidfire zone having an opening for passing gases into said radiant zone, apartition defining the inner side of said radiant zone, a water tubecluster zone adjoining said fire and radiant zones, water tubes in saidcluster zone extending the length of said boiler, a horizontal ceilingdefining the top of said cluster zone, said ceiling being'in the upperportion of said space adjacent but below the inside of the top of saidshell to form a gas dorne therebetween, said radiant zone having anopening for passing gases into said cluster zone, said twofirst-mentioned openings being spaced from each other, said cluster zonehaving an opening for passing gases into said gas dome after said gaseshave passed from said radiant zone and through said water tubes in saidcluster zone, baflie means in said cluster zone to force gases to passtherethrough in a bent path, and a flue connected to said gas dome forgases leaving said boiler.

5. In a boiler, in combination, a double shell defining an interiorspace extending substantially for the length, width and height of theinside or said shell, at least the ends of said shell defining waterlegs adjacent the ends of said interior space,'a partition extending thelength of said space intermediate the sides of said shell, saidpartition having an opening therethrough adjacent one end thereof,clusters of substantially straight water tubes extending longitudinallyfor the length of said boiler on one side of said partition, therespective ends of said tubes being supported by and being in opencommunication With said end water legs of said shell, a roof baflreextending laterally across said space on the other side of saidpartition intermediate the top and bottom of said space, said roofbaffle having an opening therethrough adjacent the other end of saidspace from said one end, a ceiling extending across all of said spaceadjacent the level of the top of said tubes, said ceiling having anopening therein above said tubes in spaced relation to said openingthrough said partition, and means for supplying and combusting fuel insaid space below said roof baths.

6. In a water tube boiler, in combination, a double shell defining aninterior space extending substantially for the length, width and heightof the inside of said shell, at least the ends of said shell defining,water legs adjacent the ends of said interior spacefa verticalpartition extending the length of said space intermediate the sides Vfor causing cornbustion air'to passiinto said space below the levelofjsaid roof battle,

of said shell, clusters'of substantially straight water tubes extendinglongitudinally for the length of said boiler on one side of saidpartition, the respective ends of said tubes being supported by andbeing in open communication with said end water legs of said shell, ahorizontal roof bathe extending laterally across said space on the otherside of said partition intermediate the top and bottom of said space,said partition having an opening therethrough adjacent one end thereofand above said roof bafi ie, a horizontal ceiling extending across allof said space adjacent the level of the top of said tubes, said ceilinghaving an opening therein above said tubes in spaced relation to saidopening through said partition, thetspace between said ceiling and roofbafile forming a a longitudinally extending radiant zone, said roofbaflle relation to provide front and rear water legs and side.

water legs, said inner shell having a crown sheet below the top of saidouter shell,a lower vertical waiter-cooled partition extending betweenthe front and rear water legs and from the bottom of said boilerupwardly about midway of the height of the top tube level in saidboiler, said partition sloping upwardly from one end to the other, an

7 upper vertical partition extending from said front water -legrearwardly to a position beyond but adjacent the midlen'gth of saidboiler and from the top of said watercooled partition to said level, thedistance rearwardly of said upper partition to said rear Water leg andbe- 8; In awa'ter tube boiler, in combination, a hollow shell havingfront and rear Water legs,'a lower vertical partition extending betweenthe front and rear water legs 7 and fromthe bottom of said boilerupwardly about mid- 7 way of the height' of the top tube level in saidboiler,-an

upper partition extending from one of said water legs to a positionbeyond but adjacent the midlength of said boiler and from the top ofsaid lower partition to said levehsaid upper partition having an openingbetween the top of said lower partition and saidlevel to, connect aradiation zone and a tube cluster zone, water tubes in said clusterzone, a roof baffle extending laterally'from one of said water legs weposition beyond butadjacent' one end ,ofsaid' boiler, means forsupporting said roof bathe, a ceiling slab extending from one sidetotheother 7 side inside saidshell in spacedlrelation and below the top ofsaidshell next to said top tube level to form a gas chamber above saidceiling slab, means for supporting said ceiling slab,'said ceiling slabhaving an openinginto said gas cha nber for the entry of gases from saidcluster zone, a transverse baffle in said cluster zone intermediate the,ends of said water tubes and having an opening between the. respectiveportions of said tubes in said clnster zone on each side ofsaidtransverse bafile,

means forsupplyingand combusting fuel and air in the space below the le'el of said roof bailieand flue means communicating with said gaschamber. v

9. In a water' tube boiler, apparatus comprising, in combination,'ashell .defining an interior space for said boiler, a longitudinallyextending generally vertical partition within said shell dividing saidinterior space into two tween the top of said partition and saidlevelforrning an 7 opening between a radiation zone and a tube clusterzone, water tubes extending between said front and rear water legs insaid cluster zoneya horizontal roof baflle extending laterally from therear water leg forwardly to a position beyond but adjacent theforepartof said boiler, a row'of relatively widely and laterally spacedwater-tubes extending between said front and rear water legs insupporting relation to said roof bathe, a vertical bank of Watertubes-in said radiation zone extending between said front and rear waterlegs substantially in th-e plane or" said lower partition and next tosaid upper'partition, said vertical bank extending from the top'of jsaidpartition to said top tube level, a ceiling slab of refractory extendingfrom one side to the'other sidein'side said inner shell in spacedrelation below said crownfsheet' next to said top tube level to form agas dome between said ceil- 7 ing slab and said crown sheet, laterallyspaced water 7 tubes across said top tube level in supporting relationto said ceil ng slab, a transverse curtain baffle-extending'- betweensaid partitions and the'side water legontheside thereof away from'saidroof baffie, said curtain bathe extending downwardly from said ceilingslab toa posi- 7 tion adjacent the lower water tubes in said clusterzone to provide an opening beneath thelower edgejofsaid curtain .bafliebetween the respectiveipo'rtions of said tubes in said cluster zone oneach side of said curtain bafiie, said ceilingslab having an openingintosaid gas dome the width of said cluster zone'and adjacent said frontwater leg to permit gases from said clnsterzone to enter the gas dome, afiu'e'at-' the other end of'said gas dome, all of said water tubesextending through the,

front and rear tube sheets at the front, and rear of said inner shell,said water tubes, roof battle and ceiling'slab being tilted upwardly'somewhat in aidirectibn proceeding from .rear tofront, a steain ontletinthe top 'ofsaid outer shell in communication with said water legs,means portions, said partition having an opening adjacent one end ofsaid space to'provide communication between said portions, generallyhorizontal baflle meanstacross said portion of said interior space onone side of said partition, said baflle extending frorn the end of saidspace adjacent said opening to a position spaced from the other end ofsaidspaee, further baflie means positioned on the other side of saidpartition to divide the portions of said interior space on said othertside of said partition into' a plurality of zones, one of them adjacentto said firstnamed opening and the other rernovedfrom said firstnamedopening, said further bafile ,means providing an opening through whichsaid Zones communicate, said last:

named opening'being spaced 'from saidfirst-named opening, flue gasexhaust means connected to said zone removed from said first-namedopening, straight water tube means extending longitudinally throughsaidinterior space on both sides of said partition, means for providinga fire on one side of said partition below oneof said battle means, andmeans interconnecting said water tubestfor thetcirculation, of watertherethrough, whereby a, low

headroom, straight water ,tube'boiler is provided with' sets of passes;forTheating'g'ases in side-by-side relation; 10. In 'a water tubeboilenapparatus comprising, in

- combination, atshell defining an interior space for said boiler, alongitudinally extending generally vertical parti tion within said shelldividing said interior space intotwo" portions, said partition having anopening adjacent one end of said space to provide communication 'betweensaid portions-bathe means positioned on one side of said named opening,said baffle means providing an opening through which said zonescommunicate, said last-named opening being spaced from saidffirst-namedopening, a

further zone extending longitudinally in'said interior space above bothsides of said partition, said further zone being in communication withsaid zone removed from said first-named opening, substantially straightwater tube' means extendinglongitudinally through said interior space 910 on both sides of said partition, means adapted to support ReferencesCited in the file of this patent a fire on that side of said partitionaway from said firstnamed zones, means interconnecting said water tubesUNITED STATES PATENTS for the circulation of Water therethrough andmeans 1,041,889 Schroeder Oct. 22, 1912 5 1,407,282 Karlson Feb. 21,1922 for removing flue gases from said further zone.

